Global incidence of non-alcoholic fatty liver disease: A systematic review and meta-analysis of 63 studies and 1,201,807 persons

Background & Aims: The prevalence of non-alcoholic fatty liver disease (NAFLD) is increasing. We aimed to estimate the pooled global NAFLD incidence. Methods: We performed a systematic review and meta-analysis of cohort studies of adults without NAFLD at baseline to evaluate the global incidence of ultrasound-diagnosed NAFLD. Results: A total of 63 eligible studies (1,201,807 persons) were analyzed. Studies were from Mainland China/Hong Kong (n = 26), South Korea (n = 22), Japan (n = 14), other (n = 2, Sri Lanka, Israel); 63.8% were clinical center studies; median study year 2000 to 2016; 87% were good quality. Among the 1,201,807 persons at risk, 242,568 persons developed NAFLD, with an incidence rate of 4,612.8 (95% CI 3,931.5-5,294.2) per 100,000 person-years and no statistically significant differences by study sample size (p = 0.90) or study setting (p = 0.055). Males had higher incidence vs. females (5,943.8 vs. 3,671.7, p = 0.0013). Both the obese (vs. non-obese) and the overweight/obese groups (vs. normal weight) were about threefold more likely to develop NAFLD (8,669.6 vs. 2,963.9 and 8,416.6 vs. 3,358.2, respectively) (both p <0.0001). Smokers had higher incidence than non-smokers (8,043.2 vs. 4,689.7, p = 0.046). By meta-regression, adjusting for study year, study setting, and study location, study period of 2010 or after and study setting were associated with increased incidence (p = 0.010 and p = 0.055, respectively). By country, China had a higher NAFLD incidence compared to non-China regions (p = 0.012) and Japan a lower incidence compared to non-Japan regions (p = 0.005). Conclusions: NAFLD incidence is increasing with a current estimate of 4,613 new cases per 100,000 person-years. Males and overweight/obese individuals had significantly higher incidence rates compared to females and those of normal weight. Public health interventions for prevention of NAFLD are needed with a special emphasis on males, overweight/obese individuals, and higher risk regions. & COPY; 2023 European Association for the Study of the Liver. Published by Elsevier B.V. All rights reserved.

Automated summary

This study aimed to estimate the global incidence of non-alcoholic fatty liver disease (NAFLD) by conducting a systematic review and meta-analysis of cohort studies. The results showed that the incidence rate of NAFLD among 1,201,807 individuals at risk was 4,612.8 per 100,000 person-years. Males and overweight/obese individuals had significantly higher incidence rates compared to females and those of normal weight.